April 4, 2014

A Smarter Auto-Pilot

by Joshua Garrett

When I was young, I loved the show Knight Rider. Not for the action or the story, but for Kitt, the talking car. Talking cars were a big deal when I was younger, as this was also the era of the original Transformers, though whenever I see toys today I wonder if anything has really changed. I was never all that interested in cars themselves, but get one that talks and you would have my attention for hours on end. Fast forward to today and we do have self-driving cars. We even have cars that can talk, but not in the way Kitt or Optimus Prime could. Even so, it is hard to deny that our vehicles are getting smarter each and every day.

Enter PILOTS, or the “ProgrammIng Language for spatiO-Temporal data Streaming applications,” an advanced new programming language for an airplane’s auto-pilot created by a research team led by Carlos Varela, an associate professor of computer science at Rensselaer Polytechnic Institute, that is able detect and compensate for faulty equipment readings. PILOTS was developed using information gathered from the tragic crash of Air France flight 447 back in June of 2009 in which was caused when readings from the pitot tubes – instruments that calculate airspeed using air pressure – were telling the auto-pilot that the plane had dropped in speed from 461 knots to 182 knots. The auto-pilot tried to correct for this, not knowing that the faulty data was actually faulty, and lowered the nose of the plane to try and increase its speed. This cascaded into a disaster as the auto-pilot then was unable to maintain its altitude and disengaged, giving control over to the human pilots who where, by that point, unable to correct for the auto-pilot’s error in judgment. It is believed that the pitot tubes were blocked by ice, preventing air from getting to them, which is what led the auto-pilot to believe that the plane was flying much more slowly than it actually was.

The PILOTS system is designed to look for any abnormalities in the data it is being given, that way it is better able to prevent disasters such as what befell AF flight 447. Rather than just rely on the information it is being given by the pitot tubes, PILOTS also monitors its airspeed using groundspeed and wind speed data gathered from other on-board instruments that monitor GPS satellites as well as forecast information gathered prior to take-off. In monitoring all three of these streams of data, PILOTS is better able to catch a mistake in its readings and prevent a possible crash. According to Professor Varela, “If we can capture the mathematical relationship between the data streams, we can look at the patterns that arise upon known failures, which we call ‘error signatures.’ Then we (PILOTS) can say ‘oh, this anomaly in the data corresponds to a known hardware failure. We know what is happening.’”

PILOTS has already been tested using the data collected from AF flight 447’s black box, and it was able to detect the faulty readings from the pitot tubes and compensate without any complications. This new system, when implemented, will help serve to make the skies even saver for flying. In addition, there are other applications for PILOTS that extend beyond the cockpit in any system that relies on sensors and could be jeopardized by faulty readings, such as in healthcare.